Mainly in a vehicle-mounted electric power conversion device, while capability of outputting a large current is required, miniaturization is also demanded. When the electric power conversion device outputs a large current, heat generated in a power semiconductor device incorporated in the power semiconductor module increases, and if a heat capacity of the power semiconductor module and the electric power conversion device is not increased, a heat resistant temperature of the power semiconductor device is reached and miniaturization is prevented. Therefore, a double side cooling type power semiconductor module that cools the power semiconductor device from both sides to improve cooling efficiency, and a double side cooling type electric power conversion device using the module, have been developed.
As an example of the electric power conversion device with such a structure, PTL 1 discloses a power module structure in which both main surfaces of the power semiconductor device configuring an arm of an inverter circuit are sandwiched between plate-like lead frames to configure the power module, and the module is incorporated in a heat radiation case for sealing and immersed in a water channel housing, and cooled from both sides.